Add hover_line_number color token (#23279)

This enables having a dedicated color for the line number hover state.
That's relevant because line numbers can now be clicked to jump to
cursor location in multibuffers.

Release Notes:

- N/A

---------

Co-authored-by: João Marcos <marcospb19@hotmail.com>

crates/theme/src/styles/colors.rs

@@ -152,6 +152,8 @@ pub struct ThemeColors {
     pub editor_line_number: Hsla,
     /// Text Color. Used for the text of the line number in the editor gutter when the line is highlighted.
     pub editor_active_line_number: Hsla,
+    /// Text Color. Used for the text of the line number in the editor gutter when the line is hovered over.
+    pub editor_hover_line_number: Hsla,
     /// Text Color. Used to mark invisible characters in the editor.
     ///
     /// Example: spaces, tabs, carriage returns, etc.